Philips 37PF7321/98 cannot turn on

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

FYI: IF you notice on that power board on the top side there are lines with slashes across them on the top and on the bottom there are similar in the areas that are not green.
these are separations between high voltage and low voltage areas.
SO, that makes the relay on a low voltage side.

Not the whole relay.

Pins 1 and 4 are on the Cold side Pins 2 and 3 are HOT.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

1st cup of coffee, I forgot a word
SO, that makes HALF the relay on a low voltage side.
or
SO, that makes the relay FEEDs on a low voltage side.
Thanks

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

Just thought Id post a pic of the wiring from the manual Its easier thn keep looking it up on the pdf.
Think we need a sharp picture of the Standby board and the hitherto unseen
SSB Board.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

we might need a picture of that board once we get an answer to see if in fact the relay clicks on and off with the white plug to it being plugged and unplugged.
It think power is getting there and the relay contacts are cooked

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

is it morning already !!

Looks like the relay might not turning on
and it is not letting the voltage go to the large bridge rectifier
before , you said it had power at both pins, but you were probably probing these two pins incorrectly (possibly at the same time ?)

since it does click, the voltage should be getting to it from the other board to 1 and 4 even though you did not get a reading the first time. (Did you unplug the small white plug while the power plug was in or did you unplug it then plug the power in)
IF you unplugged it first: try to unplug it while the power is plugged in to see if it clicks and then plug it back in while the power plug is in to see if it clicks again.
If it does not click on and off, you can try an external 5 volt source to the pins 1 and 4 of the relay(old phone adapters are around that or 4 AA batteries end for end with two wires)

FYI: IF you notice on that power board on the top side there are lines with slashes across them on the top and on the bottom there are similar in the areas that are not green.
these are separations between high voltage and low voltage areas.
SO, that makes the relay on a low voltage side.

So, if a board is loose, when you check for DC on low voltage sides, you need to use a low voltage side ground (easiest to do is usually a negative/ground pin of a capacitor)
and on high voltage sides and high voltage cap.
If the board is mounted on a metal frame, you can usually do low voltage using a frame as ground which is why they have the screw areas also marked off as low voltage side, BUT, in this case , I do not see grounding pads on the screws to allow this ?

Good morning bammbammfran. I hope you didn't have nightmare cos of my mistake in measuring voltage.

Thanks selldoor for your warning about the relay hot side.

Ok. I power up the tv with all connectors plug in. There is a click sound. I then unplug the small white connector and waited 5 sec and plug it back in. There is no click sound.

The relay click when I use external 5vDC source.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

no nightmares !!

After you applied external 5 volts to make it click , did you check the voltages out of the relay like you did before with using the main fuse for black probe and red probe to 2 and 3.
and if you saw 240 voltage on the number 2 pin, did you then check the voltages at the large capacitors
If 2 still has no power then the relay is not working.
Theoretically it could be bypassed.
Does the white plug harness have 2 or 3 wires ? if it has 3, one might be a feedback to tell the standby board that is is connected.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

no nightmares !!

After you applied external 5 volts to make it click , did you check the voltages out of the relay like you did before with using the main fuse for black probe and red probe to 2 and 3.
and if you saw 240 voltage on the number 2 pin, did you then check the voltages at the large capacitors
If 2 still has no power then the relay is not working.
Theoretically it could be bypassed.
Does the white plug harness have 2 or 3 wires ? if it has 3, one might be a feedback to tell the standby board that is is connected.

Yes, there is 240vAC at pin 2 and 3 of the relay when I use external 5vDC. There is 328vDC at both the Big Caps.

The white plug has 3 pins.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

darn but good
seems the relay is not getting powered up by the standby board for some reason
so we'll need good pictures of both sides of that board

while you have it powered on with the external 5volts, check to see if you now have voltage on the two plugs at the other end of the power supply.
the two I would check would be the 4 pin and the 3 pin that are right next to each other.
It looks like he 3 pin is ground and the 4 pin has two pins of one voltage and the other two of another voltage

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Standby and SSB boards.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Standby board without wire and back view.

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

darn but good
seems the relay is not getting powered up by the standby board for some reason
so we'll need good pictures of both sides of that board

while you have it powered on with the external 5volts, check to see if you now have voltage on the two plugs at the other end of the power supply.
the two I would check would be the 4 pin and the 3 pin that are right next to each other.
It looks like he 3 pin is ground and the 4 pin has two pins of one voltage and the other two of another voltage

The 4 pin connector now has two 12vDC and two 24vDC. You are right, the 3 pin is ground.

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

sorry I see pic just come up

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

We are going to need a pic of the bottom of the standby/audio board according to the schematic there are some transistors on there that have to do with the 5v

The picture of the standby/audio board is in message #50

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

So is the problem likely on the standby/audio board?

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

So is the problem likely on the standby/audio board?

maybe
since you are showing power as I suspected on the power supply, that should be ok
It is going to take me a bit to try to figure out where to start on this board to check for power, etc

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

Ok
this may take a while
with power supply hooked up with just the two smaller plugs that we have been dealing with from the power supply to this board connected
Let start with checking to see if the high power side of this board is putting out low power dc
check for voltage at the diode with the red circle.
You can use the jumper wire in the black circle or the negative side or the capacitor pointed to by the black arrow for the ground.

If voltage is there, let me know what it is. then check the capacitor pos side of the cap that has the black arrow.
and also check the pins at the small 4 pin connector next to the orange fuse in the yellow circle 2 reds should be + and 2 greens should be -

then--
With this board disconnected from the power supply:
switch your tester to ohms and compare resistance from the 3 pin plug that should be powering on the relay of the power board
check resistance from the blue pins to one of the black grounds and also the resistance from the red pin to ground

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

Ok
this may take a while
with power supply hooked up with just the two smaller plugs that we have been dealing with from the power supply to this board connected
Let start with checking to see if the high power side of this board is putting out low power dc
check for voltage at the diode with the red circle.
You can use the jumper wire in the black circle or the negative side or the capacitor pointed to by the black arrow for the ground.

If voltage is there, let me know what it is. then check the capacitor pos side of the cap that has the black arrow.
and also check the pins at the small 4 pin connector next to the orange fuse in the yellow circle 2 reds should be + and 2 greens should be -

then--
With this board disconnected from the power supply:
switch your tester to ohms and compare resistance from the 3 pin plug that should be powering on the relay of the power board
check resistance from the blue pins to one of the black grounds and also the resistance from the red pin to ground

There is 5vDC at the diode 6505. 0v at the cap 2533. 0v at the small connector 1M10.

I will test the resistance later. Got called for some urgent work.

[bammbammfran]

Re: Philips 37PF7321/98 cannot turn on

good
5 volts is what I was hoping for on the diode
and 0 on the small connector (I think that small connector will show voltage only when the 12 and 24 volt 4 pin connector is connected from the power supply)

next to the 5volt diode is a similar size black part at 5506
can you see any markings on it ?
I believe it is a inductor or a fuse
and it should have 5 volts at both ends. let me know on this one

one thing about these boards that sux is that they do not put a nomenclature letter in front of their numbers like R for resistor or F for fuse or C for Capacitor or L for inductor ETC

[selldoor]

Re: Philips 37PF7321/98 cannot turn on

good

one thing about these boards that sux is that they do not put a nomenclature letter in front of their numbers like R for resistor or F for fuse or C for Capacitor or L for inductor ETC

Very True! however in this case we are lucky enough to have a service manual which has a parts list.
What I do is open the pdf then press "control" "F" enter the board designator
and press next just to make sure its the part you want on the diagrams then
keep pressing next and hopefully it is listed and for 5506 you get this:
"5506 4822 157 11411 Bead 80Ω at 100MHz"

I started to look up the larger parts that I thought might be relevant to the 5volts in the area of the connector on the standby board that goes to the
relay.
There is a mosfet at 7531
and quite afew switching transistors bc817-25w and bc847bw

[john_doe]

Re: Philips 37PF7321/98 cannot turn on

I don't know whether I did something wrong or not.

The fuse 1007(the orange round fuse) is 17kohm when no power is plug into the board. Looks like this fuse is blown and there is 0v at cap 2018 and 2034.